在Django中，如何在保存前添加一个新的值给request.POST数据？

Question

我试图让用户手动输入文本字段，如果他们有许可证信息，或让它自动生成（基于表单信息），如果它的原始内容。

我被卡住了，因为从我的测试（使用打印命令）窗体正确更新与表单中给出的信息如果LicenseTag字段留空。问题是更新的信息没有被保存在数据库中。经过研究，这似乎是一个不变性的问题，这就是为什么我加了request.POST.copy()并测试了注释掉的部分定义mutability=True。

这里是我的views.py

def STLupload(request): 
    if request.method == 'POST': 
     form = NewUpload(request.POST, request.FILES) 
     data = request.POST.copy() 

     if form.is_valid(): 
      #Dis gona need alot of work 
      firstname = request.user.first_name 
      lastname = request.user.last_name 
      displayname = request.user.display_name 
      email = request.user.email 


      if (firstname or lastname == "None"): 
       if displayname == "None": 
        liscname = email 
       else: 
        liscname = '%s %s' % (firstname, lastname) 
      else: 
       liscname = displayname 


      filetitle = request.POST.get(
       'Title' 
      , '') 


      lisc = '%s %s' % (filetitle, liscname) 

      if data['LicenseTag'] == "": 

       ''' 
       mutable = request.POST._mutable 
       request.POST._mutable = True 
       request.POST['LicenseTag'] = lisc 
       request.POST._mutable = mutable 
       ''' 

       data['LicenseTag'] = lisc 
       print (request.POST.get(
       'LicenseTag' 
       , '')) 
       print ("blank") 
      else: 

      print (form) 


      #Save current username 
      comment = form.save(commit=False) 
      comment.user = request.user 

      comment.save() 

      #Flash success message 
      messages.add_message(request, messages.SUCCESS, "File uploaded successful")  

      # Redirect to the document list after POST 
      return HttpResponseRedirect(reverse_lazy('STLup')) 
    else: 
     form = NewUpload() # A empty, unbound form 

谁能帮我弄清楚如何保存生成的信息到我的数据库？

编辑＃1

Models.py

from django.db import models 

    import os 
    #import django.db.models.deletion 
    from django.db import models 
    from django.core.exceptions import ValidationError 
    from django.core.files.storage import FileSystemStorage 
    from django.utils.translation import ugettext_lazy as _ 
    from django.utils import timezone 
    from django.conf import settings 

    from django.contrib.auth.models import User 


    # Create your models here. 

    def user_directory_path(instance, filename): 
     # file will be uploaded to MEDIA_ROOT/user_<id>/<filename> 
      return os.path.join('uploads', str(instance.Title), filename) 


    def validate_file_extension(value): 
    ext = os.path.splitext(value.name)[1] 
    valid_extensions = ['.stl','.STL'] 
    if not ext in valid_extensions: 
     raise ValidationError(u'Please upload a .stl file type only') 

    def validate_img_extension(value): 
    ext = os.path.splitext(value.name)[1] 
    valid_extensions = ['.jpg','.png','.JPG'] 
    if not ext in valid_extensions: 
     raise ValidationError(u'Please upload a .jpg or .png only') 

    class UploadedFiles(models.Model): 

     user = models.ForeignKey(
     settings.AUTH_USER_MODEL, blank=True, null=True) 

     STL = models.FileField(_('STL Upload'), 
     upload_to=user_directory_path, validators=[validate_file_extension]) 
     Photo = models.ImageField(_('Photo'), 
     upload_to=user_directory_path, validators=[validate_img_extension]) 

     Title = models.CharField(_('Title of object'), 
     max_length=40, blank=False, null=True, unique=False) 
     Category = models.CharField(_('Category'), 
     max_length=40, blank=False, null=True, unique=False) 
     SubCategory = models.CharField(_('SubCategory'), 
     max_length=40, blank=True, null=True, unique=False) 
     SubSubCategory = models.CharField(_('*SubSubCategory (optional)'), 
     max_length=40, blank=True, null=True, unique=False) 

     FileType = models.BooleanField(_('Local?'), 
     default=0, unique=False) 

     Description = models.TextField(_('File Description'), 
     max_length=200, blank=True, null=True, unique=False) 
     LicenseTag = models.CharField(_('*License (optional, leave blank for original content)'), 
     max_length=200, blank=True, null=True, unique=False) 


     Xdim_mm = models.IntegerField(_('X dimension (mm)'), 
     default=0) 
     Ydim_mm = models.IntegerField(_('Y dimension (mm)'), 
     default=0) 
     Zdim_mm = models.IntegerField(_('Z dimension (mm)'), 
     default=0) 

     pub_date = models.DateTimeField(_('date_joined'), default=timezone.now) 

这是我forms.py。

from django import forms 
from django.core.validators import MinLengthValidator 

from .models import UploadedFiles 


class NewUpload(forms.ModelForm): 


    class Meta: 
     model = UploadedFiles 
     fields = ('Title', 'STL','Photo','Description', 'Category', 'SubCategory', 'SubSubCategory', 'LicenseTag') 

Answer 1

正如我所看到的，最好的方法是覆盖模型中的保存方法。

class UploadedFiles(models.Model): 
    def save(self, *args, **kwargs): 
     if not self.LicenseTag: 
      if self.user: 
       liscname = self.user.get_full_name() or self.user.email 
       self.LicenseTag = "{0} {1}".format(liscname, self.Title) 

     super(UploadFiles,self).save(*args,**kwargs) 

然后，同样的事情在您的管理员工作，而不必做很多辛苦的工作。我冒昧地优化了许可证标签的派生方式。

现在您的视图变得更加简单了。

def STLupload(request): 
    if request.method == 'POST': 
     form = NewUpload(request.POST, request.FILES) 
     if form.is_valid(): 
      lisc = '%s %s' % (filetitle, liscname) 

      #Save current username 
      comment = form.save(commit=False) 
      comment.user = request.user 

      comment.save() 

      #Flash success message 
      messages.add_message(request, messages.SUCCESS, "File uploaded successful")  

      # Redirect to the document list after POST 
      return HttpResponseRedirect(reverse_lazy('STLup')) 
    else: 
     form = NewUpload() # A empty, unbound form